board: Use CONFIG_XPL_BUILD instead of CONFIG_SPL_BUILD

Use the new symbol to refer to any 'SPL' build, including TPL and VPL

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/dhelectronics/dh_imx6/Makefile b/board/dhelectronics/dh_imx6/Makefile
index 70ca30d..7102a47 100644
--- a/board/dhelectronics/dh_imx6/Makefile
+++ b/board/dhelectronics/dh_imx6/Makefile
@@ -2,7 +2,7 @@
 #
 # Copyright (C) 2017 Marek Vasut <marex@denx.de>
 
-ifdef CONFIG_SPL_BUILD
+ifdef CONFIG_XPL_BUILD
 obj-y	:= dh_imx6_spl.o
 else
 obj-y	:= dh_imx6.o
diff --git a/board/dhelectronics/dh_imx8mp/Makefile b/board/dhelectronics/dh_imx8mp/Makefile
index e5a29fd..7bc8dc2 100644
--- a/board/dhelectronics/dh_imx8mp/Makefile
+++ b/board/dhelectronics/dh_imx8mp/Makefile
@@ -4,7 +4,7 @@
 # SPDX-License-Identifier:      GPL-2.0+
 #
 
-ifdef CONFIG_SPL_BUILD
+ifdef CONFIG_XPL_BUILD
 obj-y += spl.o lpddr4_timing_2G_32.o lpddr4_timing_4G_32.o
 else
 obj-y += imx8mp_dhcom_pdk2.o
diff --git a/board/dhelectronics/dh_stm32mp1/board.c b/board/dhelectronics/dh_stm32mp1/board.c
index 4f4f537..073f32d 100644
--- a/board/dhelectronics/dh_stm32mp1/board.c
+++ b/board/dhelectronics/dh_stm32mp1/board.c
@@ -260,13 +260,13 @@
 
 void board_vddcore_init(u32 voltage_mv)
 {
-	if (IS_ENABLED(CONFIG_SPL_BUILD))
+	if (IS_ENABLED(CONFIG_XPL_BUILD))
 		opp_voltage_mv = voltage_mv;
 }
 
 int board_early_init_f(void)
 {
-	if (IS_ENABLED(CONFIG_SPL_BUILD))
+	if (IS_ENABLED(CONFIG_XPL_BUILD))
 		stpmic1_init(opp_voltage_mv);
 	board_get_coding_straps();
 
@@ -767,7 +767,7 @@
 }
 #endif
 
-#if defined(CONFIG_SPL_BUILD)
+#if defined(CONFIG_XPL_BUILD)
 void spl_perform_fixups(struct spl_image_info *spl_image)
 {
 	dh_stm32_ks8851_fixup(spl_image_fdt_addr(spl_image));